Low capacity switching means



Dec. 4,-1934. K. WILHELM 1,932,717

LOW CAPACITY SWITCHING MEANS Filed April 25, 1931 INVENTOR KARL WILHEL BY MW L ATTORNEY UNITED STATES PATENT OFFICE LOW CAPACITY SWITCHING MEANS Karl Wilhelm, Berlin-Charlottenburg, Germany,

assignor to Siemens & Halske, Aktiengesellschaft, Siemensstadt, near Berlin, Germany, a corporation of Germany Application April 25, 1931, Serial No. 532,785 In Germany July 16, 1930 1 Claim. (Cl. 250-16) This invention relates to a low capacity switchstantially annular container being provided with ing arrangement primarily for use in high frea plurality of circumferential contacts or termiquency current work. nals.

More specifically the invention relates to a low Fig. 2 shows at 1 an annular glass tube upon 5 capacity coil switch for use in broadcast receivers. which are arranged in symmetrical manner the 60 For changing coils in broadcast receivers, refour contacts or terminal pairs marked 2, 3, 4, and course is usually had to change-over switches 5. The said glass tube or ring is suitably mountwhich usually consist of a plurality of contacts. ed upon a disk 6 which is pivotal about point 7.

In the course of operations, however, defects fre- The mercury will always be located in the bottom 1 quently arise at these contacts with the result part of the glass container and thus cause closure 85 that harmful disturbances occur in the apparatus of the pair of terminals there located. By tumduring reception. The switch devices mostly eming the container, the contact pairs 2, 3, 4 and ployed for changing coils are complicated, and, may be closed alternately and selectively. therefore, it is usual for the location of the faulty In the embodiment of the invention shown in 5 contact to be such that it is not always an easy Fig. 3 the mercury holder or tube comprises a 70 matter to correct it. triangularly bent tube 1 which is provided with Furthermore, in short wave work switches havthree terminal pairs 2, 3 and 4. It is, of course, ing the usual blades offer considerable capacity to be understood that if a larger number of terwith the result that certain undesirable interac minals are required, then the tube is given a cortion between the coils of a system would occur. pond nsly l r r n mb r of corner or sides. 75

It is the main object of the present invention to The invention provides for exhausting the merdesign a switch which may be used in high frecury tubes so that they will be substantially free quency work without introducing any of these from air and moisture with the result that the undesirable effects. contact points will always be clean and free from According to this invention, recourse is had oxidation. 80 to mercury contacts for the purpose of changing While only thre embodiments of the invention over the coils required for different wave-lengths have been shown, it is clear that other forms in broadcast receiver sets, said mercury contacts thereof could be constructed without departing of desired number being united to form a group from the spirit of the invention as defined in the and being operated by a joint operating means following claim.

such as a rotary knob or the like. I claim:

The invention will be better understood from A switch structure adapted for use in conneca reading of the following specification in contion with signalling apparatus provided with nection with the appended drawing in which, change-over elements for tuning the apparatus Fig. 1 illustrates the invention as applied to a t di fer n f q y ranges nd avin no cathree switch system; pacity reactance to affect the tuning of said ap- Fig. 2 illustrates another modification of the p ratu comprising a r ata l m a pluinvention applied to a four switch system; a d, rality of normally open pairs of contacts related Fig. 3 illustrates a third modification of the o aid el men a h p ir f contacts ei ninvention applied to a, three swit h system, closed within an evacuated container, a conduct- In the embodiment of the invention illustrated ins flu Wi hin t n in f closing a y in Fig, 1, three mercury conta ts designated 1, 2 sired set of contacts in accordance with the rotaand 3 are disposed upon a, disk 4 adapted to be rotion of the rotatable member thereby connecting tated about a center or pivot 5, Each of th aid the related interchangeable elements in said cirmercury contacts comprises a vessel of glass or c111tother suitable material 6, two terminals 7 and 8, KARL WILHELM- and a small pool of mercury 9. In such a switch arrangement it is evident that only that particular contact will be operable which happens to point downward perpendicularly, while the others will remain inoperative.

In the embodiments of this invention illustrated in Figs. 2 and 3, a single preferably circular vessel or container is provided rather than separate constituent contact units as in Fig. 1, said sub- 110 

